How to set a default PDF viewer with Android / Nextcloud

Actual behaviour

-Tell us what happens

When I open a pdf document in the Android Nextcloud app it opens a "window" where I can choose between 8 different apps to open the PDF document with.

Expected behaviour

-Tell us what should happen

It should offer me a way to set one of the readers as my default choice so that another time I skips the choice and opens PDF documents directly in the chosen viewer.

For comparison, opening a PDF document in Dropbox defaults to open the document in the embedded Dropbox PDF viewer. Similarly with Google Drive and the Drive PDF viewer, so somehow it must be possible for an app to pick a default viewer.

Steps to reproduce

1. navigate to a folder with pdf documents
2. open one
3. observe the choices of apps and lack of option to pick a default

Environment data

Android version:
7.0

Device model:
Samsung Tab A

Stock or customized system:
Stock

Nextcloud app version:
1.4.3

Nextcloud server version:
Irrelevant

Logs

Web server error log

Insert your webserver log here

Nextcloud log (data/nextcloud.log)

Insert your Nextcloud log here

NOTE: Be super sure to remove sensitive data like passwords, note that everybody can look here! You can use the Issue Template application to prefill some of the required information: https://apps.nextcloud.com/apps/issuetemplate